By 2025, we may be throwing away over 2.2 billion tons of plastics each year. Sadly, much of this plastic ends up in our waterways. Our oceans are home to enormous piles of plastic debris scattered throughout the water column. Ingestion of plastics by marine species has a substantial negative impact on their health. Additionally, plastic bioaccumulation in fish can transmit carcinogens up the food chain to our dinner plates. 

Yet despite the staggering volume of debris produced annually and the clear environmental and human health impacts, plastic waste continues to accumulate. There is an urgent need to develop novel strategies to combat bioaccumulation of plastics.

Building on the work of previous teams, the 2022-2023 team optimize the enzymatic degradation system for high-efficiency plastic degradation; validated the plastic-degrading capacity of candidate bacteria that have been identified; and determine the ways in which plastic acts as a carrier for environmental toxins.

Using adaptive selection, team members identify the most efficient PETase mutants from the existing library and selected E. coli capable of rapidly degrading plastic. They also tested the plastic desgrading capabilities of P. stutzeri using plate clearing assays, terephthalic acid fluorescence assays and scanning electron microscopy. 

Finally, the team also examined the carcinogenicity of more than 2,500 plastic additives using toxicogenomic analysis. 

Plastic Pollution: Understanding Threats to Human Health and Bioremediation Strategies

Poster by Laney Chang, Rita Glazer, Ella Gunady, Sage Hirschfeld, Alexander Hong, Jas Santos, Sophie Vincoff, Jenny Yoon, Jason Somarelli, William Eward, Beatrice Schleupner, Serafina Turner, Zack Weishampel, Newland Zhang, Zoie Diana, Margaret Morrison, Hailey Brighton, Sarah Plumlee, Thomas Schultz, Andrew Read, Meagan Dunphy-Daly  

Millions of tons of plastic pollution enter the natural environment each year, harming wildlife and potentially harming human health through widespread exposure to micro- and nano-plastics. Many plastic additives are potentially carcinogenic to humans, and we have observed microplastic internalization in liver and macrophage cells. We also identified P. stutzeri as a potential plastic degrader and validated its degradation capabilities in vitro. Finally, we successfully transformed a thermophile with a plastic-degrading plasmid, enabling high-temperature degradation.

What We Know and What We Don’t: Investigating the Carcinogenic Potential and Gene Expression Patterns of Plastic Additives

Poster by Sophia Vincoff, Jasmine Santos, Beatrice Schleupner, Margaret Morrison, Newland Zhang, Thomas F. Schultz, Meagan M. Dunphy-Daly, William C. Eward, Andrew J. Armstrong, Zoie Diana, Jason Somarelli

To better understand the potential carcinogenicity of plastic additives, we performed an integrated toxicogenomic analysis on 2,712 additives. Screening these substances across chemical databases revealed that over 150 additives have known carcinogenicity, but the vast majority of plastic additives lack data on usage patterns and carcinogenic endpoints. Based on chemical-gene interactions, both carcinogenic additives and additives with unexplored carcinogenicity impact similar biological pathways, which mainly involve DNA damage, apoptosis, immune response, viral diseases and cancer.